1. Field of the Invention
The present invention relates to a folding and fixing structure of a chair backrest, and more particularly to a folding and fixing structure of a chair backrest which can be folded or unfolded stably and can be assembled quickly by disposing rotatably folded locking structures between the backrest and the armrests.
2. Description of the Prior Art
Conventional office chairs are unfoldable, so the sizes of the office chairs 90 cannot be reduced at any time. Referring to FIG. 1, the conventional office chair 90 comprises a seat 91. A column-shaped supporting body 92 is mounted on a center of a bottom of the seat 91 and is jointed with a base 93 having a plurality of wheels. An arc-shaped positioning board 94 is fixing on a bottom edge of the seat 91, and one end of the positioning board 94 is fixing with a backrest 95. Such a conventional office chair 90 needs to be improved.
An improved folding structure of a chair is disclosed in US Serial No. 20020041121, wherein between the backrest and the seat of the chair is pivotally disposed a board having a sliding groove. The sliding groove allows for relative slide between the structures of the backrest and the seat, such that the backrest and the seat are parallel to each other after being folded (can be folded to be parallel to each other). Other related patents, such as U.S. Pat. Nos. 579,308, 4,652,051 and 4,779,926, and US Serial Nos. 20030025375 and 20020079728 disclose the improved folding structure of the chair. Thereby, a chair backrest which can be folded or unfolded stably to facilitate the folding and reduction of the size of the chair is developed.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages.